From the urn in which there are 7 red, 5 white, 3 black balls, one is chosen at random.

From the urn in which there are 7 red, 5 white, 3 black balls, one is chosen at random. What is the probability that the removed ball will be: 1) white (event A) 2) red (event B) 3) blue (event C)

1. Let’s calculate the total number of balls in the urn if we know that there are 7 red, 3 black and 5 white balls in it.

7 + 3 + 5 = 15 balls.

2. Now let’s calculate what is the probability that the ball taken at random turns out to be white. To do this, the number of white balls must be divided by the total number of balls.

P (A) = 5/15 = 1/3.

3. Find out the probability that the taken ball will be red.

P (B) = 7/15 = 7/5.

4. Let’s calculate the probability that the ball will be blue. If we know that there are no blue balls, then there is 0.

P (C) = 0/15 = 0.